Sam Baxter, 39, of Laindon, will fight her way through 200 obstacles on the 20-mile course in May.

As well as trying to make her way across the world’s largest monkey bars, which only three people have ever managed to do, she will have to crawl under barbed wire, and wade through a construction site filled with scaffolding.

The exhausting feat will be even more of a challenge for Sam after she broke her hip running a half marathon last summer.

Sam, of Monastery Road, said: “I just couldn’t walk.

“I had to have emergency surgery and they thought I was going to have to have my hip replaced this year, but I have been given the all-clear.

“There’s no doubt the course will be hard, but I did the smaller version last year and I really want to do the full thing this time.”

Contestants will face a water wipe-out zone, where they have to jump across obstacles in water, fight their way through a village in the trees and crawl over seven foot horse jumps.

Sam is back up to running five miles at a time since her accident in order to train for the competition, but she said she will be happy if she just finishes.

She said: “I haven’t got a time in mind.

“Some people do it in less than three hours, but I honestly just want to get round.”

The Rat Race Dirty Weekend takes place at Burghley House, near Stamford, Lincolnshire on May 10.